LOCALIZED STATES IN DISORDERED MERCURY-XENON MIXTURES

Optical absorption spectra in the energy range 2·0- 5·5eV have been obtained for thin films of Hg/Xo mixtures at 6 K in the concentration range X = 0·01 0·40 atomic fraction Hg. At low concentrations (X = 0·01−0·20) the films exhibit well- defined absorption peaks corresponding to trapped single Hg atoms and to Hg2 diatomic molecules. A gradual transition to continuous absorption extending to low energies, w'hich is due to larger molecular clusters, is exhibited at higher (X≥0·10) metal concentrations. Charge-transfer excitations of the clusters account for the low-energy absorption tails. © 1979 Taylor & Francis Ltd.